I've only used this mat less than a week and already there are divots in the mat from my chair wheels. I say "wheels" because my chair is a standard swivel office chair by which the wheels aren't always in the same position versus legs of a stationary chair. Not cool.
The chair mat is great and serves my purpose. The only problem is whoever packed the item put sales stickers on the mat which are difficult to remove and have left dried glue which has now become darkened on the surface of the mat. I tried to remove the dried glue several times but to no avail.